A pain measuring device for objectively measuring pain felt by a subject is suggested by the present applicant (for example, see Patent Literature 1). The pain measuring device disclosed in Patent Literature 1 has a configuration where an electrode is attached to the subject and a degree of the pain felt by the subject can be evaluated quantitatively based on a stimulation current applied from the electrode to the subject. That is, the pain measuring device disclosed in Patent Literature 1 has a configuration where the degree of the pain felt by the subject can be evaluated quantitatively by measuring largeness (current value of the stimulation current) of electric stimulation which is felt to be nearly equal to intensity of the pain felt by the subject. Further, in this pain measuring device, a stimulation current which has a frequency characteristic that the subject does not feel pain is used as the stimulation current applied to the subject.